What if... we could bring extinct animals back to life? | What If

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[dramatic music] [dinosaur screeching]

[rocket whooshing]

Science fiction sometimes has a way

of predicting the future.

I was 18 when Jurassic Park came out.

[Melanie] And it was this incredible cinematic experience.

And it put this idea in people's heads maybe.

We can bring dinosaurs back from the dead.

[upbeat music]

It was inspired by a 1991 finding.

[Melanie] Of DNA fragments found in.

A 40-million-year-old bee that was preserved in amber.

So they started to think maybe we'll find a mosquito

and inside its belly, we might be able to find DNA fragments

of a dinosaur.

A cloned dinosaur.

But no, that wasn't the case.

[Melanie] Over time, they discovered

that amber doesn't preserve DNA

as well as they'd originally thought.

And the truth is DNA sequences that are long enough

and clean enough to be used for cloning purposes.

Probably can't be older than 1.5 million years old.

But the question of whether we can bring back

more recently extinct species, that is alive and kicking.

So what if we could resurrect the extinct?

[upbeat music]

Extinction is a fact of life.

99% of things that have ever lived are extinct.

Animals usually become extinct through

what they call an extinction vortex.

The environment changes, greater pressure from predators.

The population starts to shrink. You get inbreeding.

If you're a viable offspring, you end up with a population

that's just not going to survive.

We've had five major mass extinctions.

What's unusual about now

is that we've entered into a sixth extinction

and this has been caused by us.

[pensive music]

Not only is it being caused by us,

but it's happening much faster than ever before in history.

It's estimated that about a million species are at risk

of extinction, 1/4 of all mammals, 1/10 of all birds

and 40% of all amphibians.

And we are fools if we think we can live

without this biodiversity.

[pensive music]

De-extinction is a terrible word.

It suggests that extinction's no longer a problem.

It suggests that we can make it temporary.

But to be clear, the technology is extraordinary.

[lively music]

There are three techniques, backbreeding, cloning,

and the use of CRISPR-Cas9.

Backbreeding is something

that humanity has done basically forever.

Breeding organisms together over successional generations

that have the skin deep traits that you want

to recreate in one single organism, kind of like

how we bred dogs from wolves, but going backwards in time.

[lively music] [record scratching]

Cloning is more complicated.

The transfer of nuclear DNA from the endangered

or extinct donor species to the egg of a surrogate species,

which is closely related and not endangered.

[suspenseful music]

It has been used technically

to bring back a species called Pyrenean ibex.

After many, many hundreds of failed attempts,

eventually one little animal grew to term

and this little baby was born and the room held its breath

because this was the first time ever an animal

had been brought back from extinction.

For a very short period of time

that actually weren't extinct.

A few minutes after she was born, she started

to develop breathing problems and died.

So this means it's also the first species ever

to have gone extinct twice.

[pensive music]

And so in theory, you could use that

to bring an extinct species back from the dead.

Unfortunately, it only works if the nuclear DNA

from the donor species was taken while it was alive.

You can't use dead material as a donor source,

so it can't work for a frozen mammoth.

[hopeful music]

CRISPR-Cas9 is kind of like cut, copy and paste

in a word processor but for DNA.

This is a tooth from a woolly mammoth.

In here, there will be cells

that still contain DNA from the woolly mammoth

that it came from.

CRISPR-Cas9, its use in de-extinction

is to take DNA that are still okay

and copy them into the genome of a closely related species,

say an Asian elephant, use the Asian elephant as a scaffold

and had bits of the idea of a mammoth bolted onto it.

Thick, shaggy, iconic woolly mammoth hair, for example,

or thicker, fattier skin that would allow it

to stay warmer in colder temperatures,

smaller ears that allow less heat to escape.

So scientists could actually use something like this

as a starting point for de-extinction.

Now, that sounds fascinating, crazy science fiction.

The question is is that de-extinction?

[lively music]

It's really important to recognize

that you can't in fact reverse extinction.

Once that little weave

of the evolutionary tree has been snipped,

you can't weave it back together again.

[Narrator] Done is done. You can't turn back the clock.

What we're really talking about

is creating a novel organism

to fulfill the role in the ecosystem

that an extinct animal fulfilled.

And that's a very different thing

to bringing an animal back from the dead.

[lively music]

There are some good reasons to try

to de-extinct some species.

When certain species go extinct,

they leave an ecological hole in the landscape

that is damaging.

And if we can bring that animal back, we can start

to restore levels of biodiversity.

There is this really famous story of the wolves

of Yellowstone Park.

They were exterminated from Yellowstone about 100 years ago,

but in 1995, they were reintroduced.

Nobody could believe what was going to happen.

[Helen] Their being there influenced

many other flora and fauna.

An entire kind of cascade of effects.

The wolf kills led to opportunities right the way

throughout the ecosystem.

This is the dream scenario.

Mammoths are a really good example of this.

They were involved in maintaining a habitat

called the mammoth grassland, which no longer exists

because the mammoths don't exist.

The thought is that if you bought the woolly mammoth back,

they could turn the mossy unproductive tundra into a rich

and luscious grassland.

That grassland was very effective

at pulling carbon dioxide out of the air.

So the extinction might be a big part of a response

to global warming.

[lively music]

De-extinction is a grand experiment,

filled with manifold uncertainties.

This is not plug and play.

Would it just regenerate the forest ecosystem

or would it push that ecosystem into some new state

that we've never seen before?

These systems are so incredibly dynamic.

There will be unpredictable consequences.

We have to assume those will be there right from the get go.

I think it would be ethically acceptable

to put a de-extinct mammoth back into that environment.

Those environments, they're already in terrible,

terrible trouble, and they are going to change

beyond recognition anyway.

However, we can have a better go

at achieving the same effect by using species

that exist already today

without the whole de-extinction thing.

There's a really famous quote from Jurassic Park

where Jeff Goldblum's character says,

You were so preoccupied with whether

or not you could, you didn't stop to think if you should.

[film clicking]

I think that de-extinction comes

from a profoundly emotional place.

We responded with this kind of wow,

wouldn't it be so fantastic and exciting or troubling,

we're in this Jurassic Park, you know?

The trouble with this narrative

is it's all about us again.

If we just stand there and say,

Look how amazing we have been,

then we are bringing these animals into a world

in which they have no safeguards,

no real intrinsic moral status.

People might want to sell, patent

and profit from various forms of de-extinction creatures,

and we know that this has a rollback effect

to cause huge biodiversity problems, public health issues.

I mean, look at the pandemic

and the reality that we're in now.

There's really nothing

to stop them being purely the subject to the whims

of whatever economic system happened to be there.

We could well be eating mammoth burgers

in these new Pleistocene parks.

[logos popping] [elephant trumpeting]

[pensive music]

Obviously, I would love to see a woolly mammoth.

I mean, who wouldn't love to see a woolly mammoth?

But the word is dangerous. It has consequences.

It pretends that we can solve extinction,

so it doesn't really matter if we cause a species

to go extinct, but what we mustn't do

as conservationists is be just simply anti-technology.

In doing all of this science,

in developing this technology, we will learn so much

about the way that cells and embryos develop.

It could lead to new treatments for disorders.

It could also generate knowledge that could be useful

to the field of conservation.

For example, some species that are really on the edge,

tiny populations are very inbred.

They have very little genetic diversity.

CRISPR can be used to re-engineer that diversity back in.

What would it mean to engineer coral reefs

so that they're more stress tolerant,

and can withstand warming waters with climate change?

So you can actually use all these techniques

to stop things going extinct in the first place.

That to me is a better use

of the technology than de-extinction.

[lively music]